Substance Use and Substance Use Disorders in Travelers

Introduction

Substance use disorders (SUDs) occur when the recurrent use of alcohol or drugs causes clinically significant impairment, including health problems, disability, or failure to meet major responsibilities at work, school, or home (Table 2.7.1). In 2023, 48.5 million people aged 12 or older in the United States (17.1% of the population) were estimated to have had an SUD in the past year. The prevalence of SUDs underscores the need to ensure that travelers have access to information that can reduce their risk of negative health consequences (e.g., overdose) and support recovery efforts.

Table 2.7.1: Excessive drinking and alcohol use disorder

Healthcare professionals can encourage travelers to be aware of policies and risks associated with substance use in nations where they are traveling. Substances that are legal in the United States, including medications used to treat SUDs, might be illegal in other countries (see Traveling with Prohibited or Restricted Medications chapter). In addition, travelers could encounter substances in other countries that are less common in the United States or substances that are more potent or adulterated in unexpected ways. Traveling to places where substance and alcohol use regulations and policies differ from the traveler's home (e.g., countries where cannabis use is legal or countries where the legal drinking age is lower than in the United States) could provide opportunities for people who otherwise do not use substances, including alcohol, to use them; such use could be associated with negative health consequences and other risky behaviors.

Alcohol and drug use during travel can increase risk for medical problems associated with travel, including diarrhea, heat-related illness, and motion sickness (see Travelers' Diarrhea; Post-Travel Diarrhea; Heat and Cold Illness in Travelers; and Motion Sickness chapters). Furthermore, alcohol and drugs can contribute to risks for violence, risky sexual behavior, and unintentional injury while traveling (see Injury and Death During Travel chapter).

Alcohol

According to the Dietary Guidelines for Americans, 2020–2025, adults of legal drinking age can either choose not to drink or to drink in moderation by limiting intake to ≤2 drinks in a day for men or ≤1 drink in a day for women. People of legal drinking age who should not drink at all include those with certain medical conditions, those taking medications that can interact with alcohol, and those unable to control the amount they drink or who are recovering from an alcohol use disorder (AUD). Also, there is no known safe amount of alcohol use during pregnancy or while trying to get pregnant. All types of alcohol are equally harmful, regardless of whether the alcohol is consumed in the form of beer, wine, or liquor.

On its own, excessive alcohol use can produce undesirable effects for travelers, and alcohol use while traveling can come with additional considerations. For example, even drinking small amounts of alcohol can interact with medications that may be prescribed for travel, such as dimenhydrinate which may be prescribed for motion sickness, creating adverse reactions. Also, the alcohol concentrations in alcoholic beverages consumed in other countries may differ from similar beverages in the United States. Alcohol-related policies can vary by country. For example, there may be different legal maximum blood alcohol concentration for driving; in some countries, the level is below that in the United States. Healthcare professionals can encourage travelers to avoid drinking and driving and to help fellow travelers do the same.

Excessive alcohol use

Excessive alcohol use includes binge drinking, heavy drinking, and any drinking by pregnant women or people younger than the legal drinking age. Binge drinking, the most common form of excessive drinking in the United States, is defined as consuming 4 or more drinks during a single occasion for women and 5 or more drinks during a single occasion for men. Although most people who binge drink are not dependent on alcohol, binge drinking is a harmful risk behavior associated with serious injuries and multiple diseases.

Excessive alcohol use, including binge drinking, is associated with short-term (e.g., alcohol poisoning, overdoses, injuries, violence) and long-term (e.g., liver disease, cancer, heart disease, hypertension) health conditions. Excessive alcohol use increases a person's chances of engaging in risky sexual activity (see Sex and Travel chapter), including unprotected sex, sex with multiple partners, or sex with a partner at risk for sexually transmitted infections. It is also associated with unintentional injuries (e.g., motor vehicle crashes, falls, burns, alcohol poisoning) and violence (e.g., homicide, suicide, intimate partner violence, sexual assault). Tips for drinking less include setting limits, counting drinks, managing triggers (certain people, places, or activities might tempt the traveler to drink more than planned), and being around people who support moderation in or abstinence from drinking.

Alcohol use disorder

Excessive drinking is also associated with an increased risk for AUD, a chronic medical condition. For travelers with AUD who attend 12-Step Meetings at home and wish to continue while traveling, Alcoholics Anonymous provides information on meetings occurring domestically and internationally.

Pharmacologic options are available to assist in treating AUD, including acamprosate, disulfiram, and naltrexone. Travelers who use these medicines can check with the embassies at their destination and any layover locations to make sure they are permitted. Travelers taking disulfiram should avoid beverages that might contain even low amounts of alcohol, including those labeled as "alcohol-free" beverages, as some of these products contain small amounts of alcohol (≤0.5%), enough to produce an adverse reaction. Healthcare professionals can suggest that travelers make an appointment at least 1 month before traveling if they would like to initiate pharmacologic intervention prior to an international trip. Given the potential risk for counterfeit or substandard medication, it is important that travelers carry enough for the length of their trip and understand how to store their medication.

Cannabis

The cannabis plant contains more than 100 compounds (or cannabinoids). Cannabis (i.e., marijuana, weed, or pot) refers to the dried flowers, leaves, stems, and seeds of the cannabis plant. Cannabis products include concentrates, edibles, extracts, tinctures, vape cartridges, and other products derived from the plant. Cannabis can impair coordination and distort perception, both of which may be disorienting in a place with which a traveler is unfamiliar.

Possession and use of cannabis is illegal in most countries, which can result in severe criminal penalties, including but not limited to steep fines and imprisonment (see Traveling with Prohibited or Restricted Medications chapter). Travelers are encouraged to review local laws and regulations surrounding use, possession, and transport of cannabis in cities and countries in which they are traveling and passing through. Healthcare professionals can encourage travelers to keep in mind that cannabis policies may change at home and abroad, and it can be helpful to check before each trip.

Cannabis has been legalized in some U.S. states for medical or nonmedical adult use; however, marijuana (defined as cannabis that contains more than 0.3% delta-9-tetrahydrocannabinol [THC], the main psychoactive ingredient in cannabis, by dry weight) is illegal at the federal level. It is illegal to take marijuana (defined as cannabis products with more than 0.3% delta-9 THC by dry weight) on a domestic flight. However, in the United States as of early 2024, a traveler can take products with less than this amount of THC that are approved by the Food and Drug Administration in a carry-on or checked bag.

Travelers can benefit from reviewing cruise ship policies prior to departure. For example, marijuana and cannabis products with less than 0.3% delta-9-THC (e.g., cannabidiol or CBD) may not be allowed. Similarly, reviewing the legal status of marijuana and cannabis products with less than 0.3% delta-9 THC in a destination country is important prior to departure.

Opioids

According to the National Survey on Drug Use and Health, in 2023, 8.9 million people aged 12 years or older reported misusing prescription opioids or using heroin within the past 12 months. Among persons who used prescription opioids (i.e., not only those who misused prescription opioids) and persons who used heroin, 5.7 million were classified as having an opioid use disorder (OUD) in the past year. Therefore, OUD is not uncommon in the United States, and healthcare professionals may encounter patients experiencing, or in recovery from, this condition. Preparing travelers with OUD to travel internationally requires additional planning.

Illegal opioid use and misuse of prescription opioids are factors that increase risk for overdose, with overdose deaths involving synthetic opioids such as fentanyl comprising the highest percentage of opioid-involved fatal overdoses in recent years. Even in small doses, fentanyl can be deadly. Sharing syringes or other drug equipment puts people at risk for getting or transmitting HIV and other infections. Evidence-based strategies for reducing the risk for overdose associated with illegal opioid use include access to naloxone, which can reverse an overdose from opioids, such as fentanyl, heroin, and prescription opioid medications. Fentanyl test strips can be used to determine whether fentanyl has been mixed with drugs. Travelers prescribed naloxone can check with the U.S. Embassy at their destination and any layover locations to make sure the medication is permitted and whether a prescription is required.

Medications for treating opioid use disorder

Medications are available to effectively prevent overdose, treat OUD, and sustain recovery; however, these medications might be restricted or prohibited in other countries (see Traveling with Prohibited or Restricted Medications chapter). Examples of medications used to treat OUD include buprenorphine and methadone, which act as opioid agonists. These medications reduce cravings and withdrawal symptoms by occupying and activating opioid receptors, without producing euphoria. The opioid antagonist naltrexone works by blocking the effects of opioids.

In the United States, methadone treatment programs are strictly regulated by the federal government, and methadone treatment for OUD can only be dispensed by federally certified opioid treatment programs; federal regulations describe the conditions under which methadone can be taken at home, which also has implications for travel. Some states have additional regulations. Healthcare professionals can discuss with travelers their eligibility for take-home methadone that may facilitate their ability to travel based on current regulations.

Recovery support services

Healthcare professionals can suggest that patients with AUD review information about recovery support services in other countries, such as information provided on the Alcoholics Anonymous website. Also, global support groups are available for people receiving methadone and other treatments for OUD. For instance, the German organization INDRO e.V. operates recovery support services for international travel. See Table 2.7.2 for corresponding websites.

Table 2.7.2 Website resources

Seeking substance use disorder treatment internationally

In 2023, 2.8 million or 4.5% of people reported receiving treatment for substance use disorders. A subtype of "medical tourism" (see Medical Tourism chapter) involves travel to another country for SUD treatment and rehabilitation care ("rehab tourism"). Travelers exploring this option might be seeking a greater range of treatment options at less expense than what is available domestically.

Before a traveler selects an international program for SUD treatment, healthcare professionals can encourage them to review information that can help them better understand proposed treatments. Evidence-based guidance is available from the Substance Abuse and Mental Health Services Administration as well as other organizations (Table 2.7.2).